Electric switch contact construction



Nov. 20, 1956 W. A. STREUER ELECTRIC SWITCH CONTACT CONSTRUCTION Filed Feb. 15, 1954 IN VEN TOR.

United States Patent ELECTRIC SWITCH CONTACT CONSTRUCTION Wilhelm A. Streuer, Mount Prospect, 11]., assignor to Oak Mfg. Co., Chicago, 111., a corporation of Illinois Application February 15, 1954, Serial No. 410,355

2 Claims. Cl. 200-166) This invention relates to an electric switch contact construction and more particularly to the construction of a double jaw type of contact used generally in electrical circuits carrying low power, together with the contact mounting and switch containing such contact.

For convenience the invention will be described in connection with a turret type of television tuner wherein a large number of circuits must be made and broken. In U. S. Patent 2,597,111 issued on April 22, 1952 to Albrecht, there is shown a television turret type tuner having insulating strips carrying both fixed and movable contacts. As is well known, in such a type of tuner, the turret is indexed from one position to another corresponding to the desired channel to be tuned in. At each index position, a large number of contacts are established, the insulating strip on the turret generally carrying prefabricated tuned circuits corresponding to a particular channel setting. A stationary insulating strip carrying the stationary contacts engages the movable contacts on the turret head for the purpose of establishing the desired circuits.

In the patent referred to, each individual switch or pair of switch contacts comprises a blade-like member cooperating with a pair of spring jaws. The blade is adapted to enter between the spring jaws and thus establish a firm wiping contact.

It will be evident that a construction of this general type requires accurate alignment between the various fixed and movable contacts so that the blade in any one particular switch unit will always be positioned to properly engage the jaws of the cooperating switch. This lateral alignment of switch contacts is frequently difficult to achieve and in many instances, one or two contact members will fail to be properly aligned and result in faulty operation. If any one blade-like contact is out of alignment laterally with respect to the jaws, then the blade may either attempt to engage the outside of a jaw or may enter between the jaws but spring one jaw excessively to one side with the other jaw being free of contact. This may result in permanent set to the jaws and render good contact action impossible.

Other pieces of electrical apparatus or connecting gear have generally the same problem where alignment of a large number of contacts must be secured to provide satisfactory action.

This invention provides a contact construction whereby the contact will adapt itself to substantial departure from alignment and still provide satisfactory two-jaw contact action with respect to a blade. In a device such as a television turret type tuner, the new construction makes it possible to eliminate defective tuners because of departures from strict alignment requirements. The invention will be described in connection with the drawings wherein an illustrative embodiment thereof is shown, it being understood that variations may be made without departing from the scope of the invention except as defined by the appended claims.

Referring therefore to the drawings:

Figure l is a side elevation of a part of a turret type switch mechanism as used in television tuners, for example, this constituting one example of a device to which the invention may be applied.

Figure 2 is a sectional detail on line 2--2 of Figure 1.

Figure 3 is an enlarged detail of a part of a mounting strip carrying the jaw contacts.

Figure 4 is a detail on broken line 44 of Figure 3.

Figure 5 is a side elevation of a jaw contact embodying the present invention.

Figure 6 is an exploded perspective of the contact shown in Figure 5, the two parts of the contact beingbroken and separated to show the construction.

Inasmuch as the turret tuner illustrated in Figure 1 forms no part of the present invention, it will be described in brief only. The tuner comprises frame 10 of any suitable construction having spiders 11 and 12 mounted on shaft 13 rotatable in suitable journals in end plates not shown. Shaft 13 carries knob 14 at one end thereof and carries index mechanism 15 cooperating with stationary index plate 16 at the other end thereof.

Spiders 11 and 12 form part of a rotor carrying a number of rotor contact strips 20. As is well known in this type of tuner, each rotor contact strip corresponds to one index position with the rotor generally cooperating with stator contact assembly generally indicated by 22.

Each rotor strip is of suitable insulating material and carries a number of rotor contacts 24, the strip extending parallel to shaft 13 with each rotor contact being flat and lying in a plane generally perpendicular to shaft 13.

Referring now to the stator strip, this comprises base strip 3% of insulating material extending for the full length of a rotor and anchored to frame 10 in any suitable manner. Each insulating strip 30 has disposed thereon one or more insulating strips 31. The insulating strips have rectangular apertures 35 symmetrically disposed with respect to the long side of the insulating strips. On each side of rectangular aperture 35 are slots 36 to 39 inclusive. Slots 36 to 39 inclusive have a long side extending transversely of the insulating strips with the slots being disposed generally in line with the transverse sides of aperture 35.

Each group of apertures, comprising aperture 35 and slots 36 to 39 inclusive, has a pair of contact parts cooperating to form a contact clip. Thus referring to Figures 5 and 6, one such contact clip is shown. The clip may be formed in two separate pieces or one as desired. The clip itself is of spring metal such as phosphor-bronze or spring brass and consists of members 40 and 41 of generally similar construction. For convenience, only one of these members will be described in detail, it being understood that the other member is similar except where the differences are specifically pointed out.

Referring to contact member 40, body 42 has upwardly extending soldering lug 44. The two contact members 40 and 41 as illustrated here may be joined at soldering lugs 44.

From body 42, opposite to soldering lug portion 44, each member has three strips, 46, 47 and 48 respectively. Strips 46 and 48 are both similar and have offsets 49 and 50 connecting these portions with body 42. The direction of the offset is such as to dispose strips 46 and 48 away from the cooperating body portion 41. Strips 46 and 48 are used for attaching the contact part to the insulating support and these may extend through one or both thicknesses of insulation and the extreme tips of strips 46 and 48 may be bent over to lock the contact portion in position. Offsets 49 and 50 will lie against the flat surface of the insulating support and retain the contact portion from being pulled through.

Strip 47 of the contact clip is here shown as extending straight from body 42, although if desired there may be an offset with respect to body 42. Strip 47 has the part near the end shaped and indented as illustrated at 52 to provide an offset contact-making portion. The indentation is in the direction toward the companion strip so that two indented portions 52 of a complete contact clip will face each other and in practice will press against each other in the normal idle position of the contact Due to the manner in which this contact clip is mounted, it will be apparent that contact-making strips 47 extend from body 42 for the thickness of the insulating support and beyond for a sufiicient distance to permit the blade contact to engage the same. The long unsupported jaw strips result in undesirable resilience and permit one jaw to be moved laterally so far that the other jaw will fail to follow.

in accordance with this invention, means are provided for rigidly fastening the two strips 47 at a point so near to the contact jaws that both jaws will generally move together laterally. In the form of the invention as illustrated here, strip 4-7 of member 46 has aperture 54 formed therein near body 42. Aperture 554 may be formed at any desired portion of the contact jaw between body 42 and contact-making portion 52, the differenee depending upon the clearances and tolerances of the blade contacts. Corresponding strip 47 of member 41. of the contact clip has tongue 55 punched out therefrom, this tongue being long enough to pass through aperture 54 and to be bent over so that the two strips are rigidly united at the place where the tongue passes through. Thus the effective length of strips 47 is greatly reduced thereby increasing the stiffness of the contact jaws. Preferably the contact tying region will lie within aperture 35, this being sufiiciently large to permit lateral contact movement in either direction.

This tying of the contact jaws near the contact-mak ing region serves to pull the jaws together against each other. If one of the jaws is moved laterally, the other jaw will follow, the two jaws moving laterally as a unit for a sufficiently great distance to allow for substantial misalignment. It is understood, of course, that the slots through the insulating material are large enough to permit the lateral movement of the contact jaws.

Cooperating with the contact jaws are contact blades 58 suitably attached to insulating strips in any desired manner. As a rule, contact blades 58 may have a general arrow head shape with lateral spikes so that they may be anchored in the insulating strip. Such a construction is illustrated in the patent previously referred to, although other constructions are possible.

By virtue of the present invention, contact clips of thin stock may be used, the jaws being quite long in comparison to the stifiness of the metal to allow for mounting of the jaws upon the rear face of an insulating support. The locking together of the contact jaws as described permits a more flexible contact design and makes it possible to have various body shapes. The locking of the two jaws may be accomplished by staking, riveting, or any other means.

What is claimed is:

l. A multi-contact switch construction for television turret tuners or the like comprising a stator carrying at least one elongated insulating stator strip with a plurality of contacts rigidly secured thereon, said contacts being disposed in side-by-side relation along the length of said strip, a rotor carrying a plurality of elongated rotor strips, said rotor axis, stator strip and rotor strips being parallel, the rotor strips being movable with rotor movement past the stator strip, each rotor strip carrying a plurality of rotor contacts rigidly secured thereto, each rotor contact having a cooperating stator contact, a pair of cooperating rotor and stator contacts having the following construction: one of said cooperating contacts having as the active part a blade whose plane should be perpendicular to the rotor axis, the other cooperating contact having a pair of spring jaws extending toward the blade contact when a pair of contacts are in circuitclosing condition, the blade and jaws cooperating so' that the leading edge of the blade is a side edge and the cooperating jaw edges are also side edges, said jaw side edges, being flared away from each other so that the blade may enter properly, said jaws being springable to separate when said blade enters between said jaws, the other cooperating contact having a mounting portion for securing to the insulating-strip and having in intermediate portion between each jaw and mounting portion, the intermediate portion for one jaw being 'apertured and the intermediate portion for the other jaw having a tongue out out therefrom and extending through the aperture of the one jaw with the tongue bent over to lock the twojaws together, said jaws extending substantially straight from their intermediate portions, the tongue and aperture for the jaw contacts being substantially midway between the sides of each jaw portion, said contacts during assembly being susceptible to misalignment whereby any blade entering between the open jaw tips of a cooperating contact even though out of alignment will finally make firm contact between the contact-making portions of the jaws, the tongue and slot arrangement serving to maintain the jaws together, said blades and jaws being free for accommodation.

2. The construction according to claim 1 wherein the rotor strips carry the blade contacts and the stator strip carries the jaw contacts.

References Cited in the file of this patent UNITED STATES PATENTS 1,451,296 Gibbons Apr. 10, 1923 1,841,736 Jones Jan. 19, 1932 2,177,483 Hall Oct. 24, 1939 2,594,111 Albrecht Apr. 22, 1952 2,628,292 Mastney Feb. 10, 1953 

